For the first time in two years, the lights were on inside Holocaust Museum Houston. Music wafted down Caroline Street. Excited chatter and the click-click-click of high heels on hard floor escaped every time doormen opened the new building's glass double-doors.

Saturday night in the Museum District sounded like a party. And party is exactly what some 800 "First Look Celebration"-goers did.

HMH officially opens its Lester and Sue Smith Campus to the public on June 22, though last weekend, major donors, Holocaust survivors and dignitaries caught a sneak peek of the now 57,000 square foot facility.

The original structure was one-story and 21,000 square feet. Now it's the fourth largest Holocaust Museum in the country and LEED certified.

Against a sea of gowns and tuxedos - though invitations suggest black-tie optional attire, most erred on the formal side - the prominent Butterfly Loft sculpture was impossible to miss, and provided a striking backdrop for guests angling to photograph the historic occasion. The kaleidoscopic swarm of 1,500 winged creatures spanned all three floors, with each butterfly representing 1,000 children of the 1.5 million children who perished in the Holocaust.

The first floor features the Morgan Family Welcome Center and three galleries: Bearing Witness: A Community Remembers Holocaust Gallery; the Rhona and Bruce Caress and Still I Write: Young Diarists on War and Genocide Gallery; and the Lester and Sue Smith Human Rights Gallery with the Interfaith Pool of Reflection. The naming of the latter doubled as a surprise "thank you" announcement for the Smith family; two years ago, philanthropists Sue and Lester Smith pledged a $15 million matching grant toward HMH's $34 million expansion, the largest gift in the museum's history.

For party purposes, the ground floor also housed the first of Chef Smirnov Catering's kosher delicacies and the electronic Moodafaruka band. Sushi and bruschetta grazing stations flanked a central bar where mixologists poured light-colored spirits - no stains, please! - including champagne, white wine and a strawberry signature cocktail.

On the second floor, a ravioli bar and Divisi Strings performance activated shortly after Sue Smith delivered brief remarks.

"Holocaust Museum Houston has always been very important to our family," she said. "We are so proud to have our names forever linked to this institution that serves as a beacon of light in our community, a place that inspires us to be our best selves, to speak up and live lives of courage and conviction."

Her poignant address ended with a quote from her late husband, Lester. "'When we all gather together to open those museum doors, let us walk side by side, in peace, in memory and in the hope of a world where we can all serve as champions of what is right and just.'

"From his mouth to God's ear," Sue said. "Let it be so."

She was later spotted upstairs on the third floor where John Acevedo played flamenco jazz on guitar and dessert was served. The Boniuk Library level proved to be quite the hot spot. Bold-face altruists such as Margaret Williams were among those indulging at the admittedly addictive cookie spread. Chocolate chip, in particular, quickly became the evening's most coveted bite.

Patrons took home souvenirs, too. Commemorative coasters made from Jerusalem stone were distributed as parting gifts.

Celebrations ended just before midnight, and resumed the following morningwith Rabbi Israel Meir Lau's ribbon-cutting.

And starting June 22, the museum's grand re-opening kicks off with two touring exhibitions: "Operation Finale: The Capture & Trail of Adolf Eichmann" and "Points of View."